Even as a proponent for SDR (and an SDR "user"), the lingering thought in my mind regarding SDX in space is survivability.
There is no flight heritage (yet) for an SDX in space, and there is quite a bit of complexity with regards to software and integrated components (ADCs, DACs, FPGAs, CPUs, etc.).
But these problems plague analong XPNDRs as well....with the right selection of components, de-rating of components, and rad-hardened when feasible, chances for success increase.
73,
Dave n0tgd
On 9/30/07, David B. Toth ve3gyq@amsat.org wrote:
Patrick: it is too bad that you were unable to join us here in Hartford, CT this weekend for the TAPR-ARRL DCC ... There were many presentations on SDR, some by AMSAT personnel ...
The hardware does not GET any simpler than in SDX ... the HUGE advantage is that a component with a shifting value (such as might occur in a spacecraft with wide temperature swings) does not degrade the performance/optimization of a device, because if the hardware does age/shift, then that can be compensated for in software ...